Recipes and Instructions

The recipes and instructions that follow are suggestions based on my own experience and research. They are intended to serve as a collection of helpful tips and resources for painters

Disclaimer: Although I use these recipes and instructions on a regular basis myself, I offer no guarantees and disclaim any responsibility with regards to resulting damages or losses incurred though the use of the following information.

Heat the mixture gently in a double-boiler until the RSG has been fully dissolved and add the alum solution. WARNING: Do not allow the temperature to exceed 60°C (140°F) as the glue begins to break down at this point.

The glue can be applied warm to hand-mounted, not-too-tight canvas. Using a large brush, work vigorously using circular motions to ensure the glue penetrates the surface evenly. The fabric will tighten instantly and become even more taut as the glue dries. Watch out, this tension can actually tear weak or overstretched fabric and even snap poorly built stretchers! The larger the canvas, the stronger the tension therefore the less tight it has to be before being sized.

Apply one or two more coats, allowing the surface to dry completely and sanding lightly between each application.

Once properly sized, the canvas is ready to be painted. If you want, you can add a layer of gesso to change the strength, color and texture of the ground.

The leftover glue will keep for a few weeks in the fridge and can be reheated when needed.

*RSG is a natural product and as such will vary in strength from one batch to another. You can test your glue by allowing it to cool down and gel after Step 6. At this point the desired consistency for canvas should be firm but friable, easily crushed between the fingers. If the gel is too stiff or too soft, you can alter the proportions accordingly.

For sizing wood panels stronger glue may be prepared by increasing the concentration of RSG. On thinner panels, it may be advisable to size both sides as the tension may warp the board.

For sizing paper for watercolor or ink a much thinner solution will suffice.

Boiled Linseed Oil* Gesso Recipe

*Boiled linseed oil—also sold as linseed oil varnish in hardware stores and by Kremer—is intended for use on wood as a protective coating (really nice, by the way) It usually contains drying agents and will yellow considerably over time. It is definitely not a good idea to use it as a painting medium, but for a gesso, it should be fine (again, no guarantees 🙂 )

Pour some boiled linseed oil in a mixing bowl and gradually add fine chalk (Blanc de Meudon, if you can find it), ideally sifted through a fine sieve, as you mix.

Don’t mix too vigorously, to avoid forming to many bubbles.

You may add a fine pigment of your choice (most likely titanium white), or even some paint directly from the tube (it’s probably a good idea to stick with fast driers in that case: burnt umber, mars black, ockers, ultramarine…)

Keep adding chalk until the mixture is fairly thick and harder to mix but still runny and completely homogeneous (no lumps). Your looking for a consistency akin to that of pancake batter. That being said, the consistency is really a matter of purpose and taste, but do bear in mind that the less chalk there is the more oil there is (relatively speaking) and, as such, the gesso will take longer to dry (for a given thickness).

Apply with brush, palette knife, sponge or whatever tool any way you like. One can obtain very nice textures with a thick mix.

Allow to dry for at least two weeks. This may seem like a long time but if you prepare a few canvases in advance, it’s really not an issue. Painters in a hurry can go buy pre-stretched, pre-gessoed, pre-botched, over-priced canvas if they like!

Sun Oil Recipe

Place a sheet of glass over the tray to protect the oil from dust and debris.

Using a few matches or something similar, create a small gap between the glass and the tray to allow air flow.

Place the tray on your sunniest windowsill. The oil will react with the air and gradually thicken. Sunlight accelerates this process and also bleaches the oil over time resulting in a realively non-yellowing oil

Agitate the oil every week or so to prevent the formation of a film on the surface.

When the oil has the consistency of honey, it may be filtered in a cheesecloth to remove any impurities such as dust or small insects.

It can now be bottled in a clear glass container and is ready to use.

The oil may be stored in direct sunlight to further the bleaching process.

Handmade Paint

Making a Brush Bath

Although most oil painters clean their brushes with a solvent and I do the same from time to time. I have found that using a slow drying oil such as walnut oil to clean my brushes has the double advantage of being non-toxic and of being better for preserving the natural hairs and bristles. (For synthetic brushes, just solvent should be fine)

Using a drill, make a bunch of small holes in a plastic jar lid.

Place the lid right-side up at the bottom of a larger jar or metal can.

Pour in enough oil (or solvent) to immerse the lid.

Clean your brushes by working them against the holes in the lid. The pigment will dissolve in the liquid, run through the holes and settle at the bottom of the can.

Wipe off as much of the oil/solvent as possible from the brush hairs using a rag.

Remember that the leftover oil on the hairs will dry out if a brush goes unused for more than a week. One should clean unused brushes with soap (Savon de Marseille is a good choice, but any soap should do) and warm water before reaching this point.

Now and then, the leftover pigment sludge that has collected at the bottom of the can may be cleaned out, set aside in an airtight container and reused (as a background color, for example).

Don’t Clean Your Brushes!

It is possible to eliminate the tedium of cleaning brushes altogether. By keeping the brush’s bristles immersed in oil, there is no risk of them ever drying out. Evidence from older paintings show that this was common practice back in the day. This method is especially good for fine brushes and can help to significantly extend their lifetime.

Partly fill an inclined tray with a slow-drying oil such as walnut or poppy.

Lay your dirty brushes in the tray, with the bristles submerged in the oil.

Using the brushes again is a simple matter of twirling them in a bit of turpentine or clean oil and wiping them off.